I needed to add tab key support to a GUI.TextArea and soon discovered it was not quite as easy as I had originally thought. I have provided two code examples below. The first example is simplified and the second example is more complex that wraps TextArea controls inside of parent control.

With these examples you can type text in a TextArea/TextField and press the tab key to insert 4 spaces, or press Shift+Tab to move the line 4 spaces to the left if the area is clear.

I have also provided a third advanced example from my UIControls library to give an example of a real word usage scenario. This third example synchronizes my TextBox control with the unity’s TextEditor. My TextBox control has similar properties as Winforms TextBox.

If you need your editor scripts to have the same functionality as “Assets->Show In Explorer” check out the cross platform method EditorUtility.RevealInFinder. This method is currently undocumented in Unity 5.2.1.